A 1000-W UV radiation (UVR) source (Lightning
Cure 200, Hamamatsu, Japan) was used for deliver-
ing solar-simulated radiation to pig skin. The lamp
was combined with a dichroic mirror assembly re-
flecting most of the visible and infrared emission, to
reduce the heat load on the skin, and with a 1-mm
WG295 Schott selective UVB band-pass filter (295
nm) to eliminate wavelengths less than 295 nm. A
1-cm diameter liquid light guide was connected to
the exit port of the lamp housing to deliver energy to
the surface of the skin. The light guide was posi-
tioned just above the surface of the skin. The inten-
sity used in the experiment was 5 mW/cm2 of UVB
as measured by a research radiometer (IL1700, In-
ternational Light, Newburyport, Mass). At this irradi-
ance, there was about 40 mW/cm2 of UVA; because
of the much greater erythemal effectiveness of UVB,
the latter is expected to be the dominant wave band
in the observed biologic effects.